Food produces heat is calculated in calories, calories used in nutrition is kcal, its calories is to make a kilogram of water one degree Celsius when the heat required. 1 gram of protein in the body after absorption and oxidation of 4 kcal calories, 1 gram of sugar in the body after absorption and oxidation of 4.1 kcal calories, 1 gram of fat in the body after absorption and oxidation of 9.3 kcal calories, 1 gram of fat in the body after absorption and oxidation of 9.3 kcal calories, 1 gram of fat in the body after absorption and oxidation of 9.3 kcal calories. One gram of protein produces 4 kilocalories when absorbed and oxidized in the body, one gram of sugar produces 4.1 kilocalories when absorbed and oxidized in the body and one gram of fat produces 9.3 kilocalories when absorbed and oxidized in the body. From the above figures, the calories of food can be calculated from its composition, for example, every two bread contains 11.1 grams of carbohydrates, 0.6 grams of fat, and 3.1 grams of protein, then 1

lb of bread produces the following calories:

Carbohydrates 16×11.2×=716.8 kcal

Fat 16×0.6×9 = 86.4 kcal

Protein 16 x 3.1 x 4 = 198.4 kcal

Total 1001.6 kcal

Each person has a minimum number of calories needed to maintain life, usually men need 1700 kcal per day. Women need 1400 kcal per day, in addition, due to different occupations, the energy consumed by each person is also different, so the need for additional calories, which in addition to the increase in calories between 1000 ~ 3000 kcal, as for the calories needed by children according to their age, but also depending on the size of the body and the number of activities to decide, the following table is the average number of calories needed daily:

Children 1650 kcal before 6 years old

6 to 10 years old 2300 kcal

10 to 14 years old 2700 kcal

Female 2300-2750 kcal

Male 2750-5000 kcal

Miners, smiths, blacksmiths, and other workers have the same calorie needs as the rest of the population. Blacksmiths. Sawmill workers and other heavy physical exertion of people, its calorie needs are higher than the average person, each person may need more than 5000 kilocalories per day.

2. Dietary value of bread

Bread is the most complete nutrient content of human food, the reason is that the bread is usually lack of nutrients is fat, but eat bread, often with butter or macaroons. Because its main ingredient is carbohydrates, so people like to eat with high fat or protein containing foods, whole wheat bread and white bread nutritional value is not the same, which are as follows:

White bread and whole wheat bread composition comparison

Water content Protein Fat Starch Fiber Minerals

White bread 40.0 6.5 1.0 51.2 0.3 1.0

Whole wheat bread 45.0 6.3 1.2 44.8 1.5 1.2

From the above table, it can be seen that white bread contains more protein and less fat than whole wheat bread.

3. Special types of bread:

Danish bread - contains several times more fat than white bread, about 30% of the fat and wrapped in stuffing, enough to compensate for the calories consumed by working in cold areas, when we know that the oxidation of fat must be matched with sugar, so we need to consume the right amount of fat and sugar every day in order to meet the principle of nutrition.

Sweet bread - beautiful appearance and sweet flavor, is the characteristics of this type of bread, usually in the production of eggs and filling, so it also provides most of the vitamins and minerals.

Wheat rind bread--Wheat rind contains most of the B vitamins, and this type of bread is made with about 15% of wheat rind, and we know that B vitamins can prevent beriberi and nourish nerve cells.

Cheese bread - every 100 grams of cheese contains about 23.9 grams of protein. 32.3 grams of fat. Sugar 1.7 grams. Calcium 873 mg and other minerals, vitamins and so on. And usually cheese bread contains about 10% cheese.

Raisin bread - more nutritious than other fruits, grapes, increased nutrition in the bread, such bread generally contain more than 50% raisins.

4. Digestibility of Bread:

Flour proteins that have been cooked or baked are more easily digested, and because the gluten it produces comes into easy contact with the digestive juices, bread is easier to digest than any other food. Wheat's protein is the best of all cereals, but it is still a second-tier protein, and because it cannot be fully utilized in the body, it is appropriate to add animal protein to our meals. However, the nutritional value of bread with milk powder added during the production process is even more enhanced.

Fat is usually easy to absorb, and the digestibility of fat is affected by its melting point. The melting point of fat in wheat is 50°F, and it is usually liquid, so it can be easily digested, and since most of the fat in wheat is concentrated in the germ, germ bread is easier to digest than ordinary bread.

The digestion of bread begins in the mouth, and the salivary digestion is the transformation of starch into dextrin and maltose, and the amount of the transformation depends on the degree of completeness of the bread chewing, the location of the fresh bread due to the water content, in the mouth and saliva contact less, so the degree of digestion in the mouth is also less, but baked toast or cookies in the mouth to digest the degree of more complete. When chewing, the dry food promotes the secretion of saliva so that saliva is completely mixed, bread in the digestion of the nutrients lost.

The crust of bread is easier to digest for this reason, and bread remains in the stomach for about 3.5 hours until its protein properties change. Fresh bread forms coarser lumps in the stomach and is less likely to be saturated with digestive juices. It is in the small intestine that the digestion of the starches and proteins within the bread is complete and where absorption takes place.

Comparison of the digestibility of various types of food and bread

Type of food Protein Fat Carbohydrates Energy that can be utilized (%)

Dairy products Milk Cream Yogurt 97 95 98 93

Cereals (including bread) Vegetables Eggs Fruits Meat and Fish Dried pulses compared with meat, the loss of protein in digestion (about one-fifth), cereals are more pronounced. one-fifth) is more pronounced with cereals. But the absorption rate of mineral salts is certain, so although the mineral content of whole-wheat bread is higher, but also can not be fully absorbed. The absorption rate of proteins varies according to the amount of carbohydrates contained in the food. With this diet (if whole wheat bread), the protein absorption rate is as high as 95%.

Whole-wheat bread does not absorb as many nutrients as white bread when it is digested because of its high fiber content. The bran-like fiber prevents the digestive juices from binding the nutrients tightly together.

The stimulatory effect of wheat bran on the small intestine is important, especially for some people. Whole wheat flour is not fully absorbed because of incomplete milling. If the husk is milled as fine as flour, its absorption rate will increase and its mineral salts will be more easily absorbed. Therefore, at present, we all love to use the fine grinding of flour.

The other important nutrients in bread are vitamins and mineral salts. They are found in different amounts in different parts of the wheat. The endosperm of wheat contains the least amount of protein, but the closer it is to the husk, the higher its protein content, so the proportion of protein in high-gluten flour is higher. The protein content of wheat is also high in iron, vitamins and nicotinic acid. The germ contains a lot of protein, iron and vitamins. The germ contains a lot of protein, iron and vitamins, and the cotyledons contain more vitamin B than the bran. The principle was discovered during World War II that the cotyledons of wheat could be separated and added to the various flours that existed in different countries. This was one of the major achievements of the Cereal Research Association during World War II. The cotyledons make up only 1.5 percent of wheat by weight, but they contain about 59 percent of the vitamin B.

Phytic acid has a big influence in the process of flour making. This is because this acid contained in the bran forms insoluble calcium salts in the body during digestion. The calcium that binds to phytic acid in the body comes from food, such as milk and eggs. Therefore, the combination of insoluble calcium salts can lead to calcium deficiency and the formation of achondroplasia. This was the case in Ireland during World War II, when whole wheat flour was used and there was a lack of other supplemental foods. The effect of calcium phytate on absorption has been studied in the United States for a long time and is becoming better understood. When 85 percent refined flour was used, seven taels of calcium were added to each bag (lime was substituted). Later, when 90% refined flour was used, 14 taels of calcium were added per bag. This standard has been in use since 1946.

At 85 percent refined flour, the amount of phytic acid is three times that of 72 percent milled flour, and up to six times that of whole wheat flour. Cereals contain the most iron in the outer skin.

Iron content of flour

Fineness (flour) Iron content (mg/100)

100% 3.1

85% 2.2

80% 1.7

70% 1.4

It can be seen that the amount of iron content of unadulterated flour is different according to the degree of refinement.

The table below shows that whole wheat flour contains more iron than white flour. However, the amount of iron absorbed in the body varies depending on the body's needs and the amount of iron in the food. Not all of the iron contained in whole wheat bread is absorbed, because it is difficult to absorb such a complex organic molecular structure. Whole wheat bread contains a protein that is not found in white bread, which makes iron insoluble, i.e., it prevents the absorption of iron in the small intestine. Whole wheat bread contains phytic acid, which is completely insoluble. In addition, phosphoric acid and iron will also form insoluble iron phosphate. Therefore, a small amount of iron should be added to all kinds of flour.

5. Vitamins in Bread:

A. Vitamin A - There is almost no Vitamin A in ordinary white bread. If unbleached flour is used to make bread, a small amount of carotene may be present in the dough. However, when baked, they are all destroyed by oxidation. The amount of vitamin A in germ bread is also very small, although it contains more carotene, but the germ is more susceptible to the effects of heat, so it is roughly lost after baking. The butter that is added during the production process, in particular, does not contain any vitamin A at all after baking.

B. Vitamin B--The most important vitamins in bread are B1 (anti-neuroinflammatory), B2, and nicotinic acid. In addition to the three mentioned above, there are more than four other B complex vitamins present in food, such as vitamin B6 pantothenic acid, biotin and folic acid, which are missing in bread.

In 85% refined flour, some vitamin B is still present, but roughly one-fifth is lost during baking. Although recent studies have shown that it is not as high as one-fifth. But if baking soda is used as a bulking agent, all the B vitamins are destroyed.

Sometimes a deficiency of vitamin B1 is caused by an irregularity in the digestive tract, such as an ulcer in the stomach or intestines.

Whole wheat bread and germ bread are highly recommended foods because they contain high levels of vitamin B1.

If the bread is made with enough yeast, it can supplement the vitamin B1. However, adding 30 to 60 taels of yeast per 280 pounds of flour is not very useful, but only enhances the content of B1.

Wheat germ contains more B1 and B2, but yeast contains more B2 than B1. Vitamin B2 is more stable than B1, although both are heat stable.

Some things to know about whole wheat bread:

(a) Whole wheat bread without germ contains less vitamin B2 than whole wheat bread with germ, but more than white bread.

(2) Germ bread is not as nutritious as people think. Its vitamin B1 content is only slightly more than ordinary whole wheat bread, but than white bread is several times more.

a. Vitamin B2 - Riboflavin is found in all germ breads, but less in white bread.

b. Niacin - found in wheat, yeast and germ.

c. Vitamin B6 - less in wheat, more in yeast.

If the yeast content in bread can be as high as 0.4% of the actual percentage, the amount of Vitamin B2 is sufficient to supply the body's needs.

When bread is made with chemical bulking agents, it is easy to destroy Vitamin B1. There are many such breads on the market today, and people with stomach problems often eat them, so it is worth noting the lack of B1.

C. Vitamin C -- Vitamin C is not found in cereals.

There is an attempt to promote a type of tomato bread, but Vitamin C is highly unstable, so it is questionable whether the final product contains Vitamin C.

But it is not a good choice.

But Vitamin C can enhance the flavor of bread. For example, eating bread or crackers with pudding juice or orange juice is very tasty.

If the bread is baked twice, the vitamin C is completely absent, due to oxidation in the dough, not the nature of the vitamin.

D. Vitamin D - in the form of D2 and D3 - is initially dissolved in a vegetable oil used in bread. After baking, the vitamin D remains. For example, two pounds of dough that originally contained 280 units of vitamin D would still contain 247 units after being made into bread.

This ultraviolet light was once used to irradiate the dough, but the increase in Vitamin D was minimal, and only ensured the effectiveness of D2.

From the point of view of children's diets, it is very beneficial to eat bread containing this vitamin, but there should be a limit to the amount of vitamin that can be used.

E. Vitamin E - contained in germ bread.

E. Vitamin E - contained in germ bread.